Flux-switching permanent magnet (FSPM) machine is a relatively novel brushless machine, which exhibits inherently sinusoidal PM flux-linkage, back-EMF waveforms and high torque capability. However, the air-gap field density is difficult to be regulated since it is produced by the stator magnets alone. Hence, hybrid-excited flux-switching (HEFS) machine is proposed by introducing a set of field windings into an original FSPM machine. However, in HEFS machines the flux linkages of armature windings vary in inverse proportion to the air-gap flux density when significantly saturated, which is different from the conventional machines. So in this paper, the oversaturated phenomenon in HEFS machines is explained and the effect of saturation, especially due to magnet material, on the relationship between air-gap flux density and armature flux linkage is investigated based on 2-D finite element analysis. Also, an effective stator-tooth-width coefficient (kstw) is defined to evaluate the oversaturated effect quantitatively.@en

In this paper, a nonlinear magnetic network model (NMNM) is proposed to predict the electromagnetic performance of a hybrid-excitation flux-switching (HEFS) machine, in which the modeling of the magnetic motive forces (MMF) due to field windings is specifically investigated. The proposed NMNM enables the predictions of air-gap flux-density distributions, flux linkage, back-electromotive force (back-EMF), and inductances of both armature and field windings under different excitation conditions, including pure magnets, pure field currents, and hybrid excitations. The predicted results from the NMNM model are validated by 2-D finite element analysis.@en